Frequency modulated continuous wave (FMCW) radar and chirp sequence modulation are two exemplary types of modulation which are used particularly frequently in automotive radar systems. The chirp sequence modulation is used primarily in corresponding radar sensors, which in contrast to the FMCW method allows the sensor parameters distance and speed to be ascertained separately from one another. For this purpose, a sequence of multiple identical, linear frequency ramps is emitted. In order to reduce memory requirements when explicitly programming each frequency ramp, a ramp generator offers the option of using data for the frequency ramps from a memory multiple times.
Conventionally, the chirp sequence modulation is supplement to the effect that the sequence of the frequency ramps itself represents a superimposed frequency ramp, for example as is described in German Patent Application No. DE 10 2014 212 280 A1 and DE 10 2012 212 888 A1. The center frequencies of the frequency ramps must thus rise continuously, as a result of which it is not possible to use a mechanism for repeating the frequency ramps, and thus data for every ramp signal must be explicitly stored in the memory. This means increased memory requirements, and due to the limited data rate of the control interface also a longer time for programming the ramp signals.
U.S. Patent Application Pub. No. 2010/0289692 A1 describes a method of a modulation sequence for generating ramp signals for radar sensors.